1. Field of the Invention
This invention relates generally to pallets and other structures designed to contain, support, and aid in the transport of cargo. This invention relates more specifically to such pallets and structures that are constructed primarily of corrugated cardboard.
2. Description of Related Art
Structurally sound pallets are essential tools in the cargo shipping industry throughout the world. Whether cargo is being shipped by land, sea, or air, the handling of material necessitates the use of a practical means of supporting and moving unit amounts of goods.
The most common form of the shipping pallet is constructed of wood and is configured in one of two basic designs A first wooden pallet design is constructed of 2".times.4" wooden members, three to a pallet, which are laid parallel, on edge, and are cross connected by a series of 1".times.4" or 1".times.6" slats which form the top surface of the pallet.
A second wooden pallet design is constructed of nine or more discrete wooden blocks which function as spacers between two layers of parallel flat wooden slats. The advantage of this latter configuration is that it is approachable by a fork lift or other standard pallet moving device from any of its four sides. The 2".times.4" design on the other hand is approachable only from two sides that are opposite each other across the pallet.
The disadvantages of both wooden pallet designs derive primarily from the fact that they are constructed of wood.
A first disadvantage is the fact that wooden pallets are typically very costly. Not only is the wood product itself expensive, but the configuration and construction of the pallet is complex and costly as well. Wood continues to become a scarcer and more valuable commodity, and recent concerns over the availability of harvestable trees have only increased wood's value and have spurred society's move towards substitute materials.
A second disadvantage derives from the fact that wooden pallets have the potential for damaging a finished surface that the pallets might be used upon. In addition to the wooden members themselves being a problem, the nails used in the construction of most wooden pallets are also likely to cause damage. It is nearly impossible for someone utilizing a wooden pallet on a sensitive surface to move cargo without causing some damage to that surface.
A third disadvantage to wooden pallets relates to their potential for damaging the cargo that is placed upon them. The same defects, splinters, and nails, that can damage floor surfaces can also be found on the support platforms of wooden pallets and can easily catch and cut into cargo being transported.
A fourth disadvantage of wooden pallets relates to their excessive weight. Whether the construction is of the 2".times.4" design or the wooden block design, the heavy weight of the typical wooden pallet limits the ability of an individual to carry one, or at most two pallets when empty. Furthermore, while the cargo being transported on a pallet typically outweighs the pallet by a significant amount, the weight of a wooden pallet is substantial enough to be an important factor when determining the overall weight of a load being shipped.
In spite of their disadvantages, wooden pallets do have the advantage of being reusable for a certain period of time or for a certain number of cycles of use. Inevitably, however, a wooden pallet will be damaged to the point that it can no longer safely transport cargo. At such a point, the damaged pallet becomes a disposal problem and can frequently end up occupying a large amount of space in disposal landfills.
It is estimated that over half of all shipping pallets are not returned to their point of origin after use. This means that the shipper must continuously buy new or used replacement pallets and to a great extent relies on the general circulation of used wooden pallets to provide a supply that is more cost effective than merely the purchasing of an unused new wooden pallet. Relying on this uncertain supply can be costly if a shipper's demand for pallets does not coincide with the arrival of a corresponding supply of used pallets. If a pallet user could rely on a constant supply of inexpensive pallets that did not fluctuate with the availability of recycled used pallets, it would certainly be to his advantage.
Cardboard pallets have been conceived of and utilized for quite some time as an alternative to wooden pallets. Cardboard pallet designs that have been used in the past have solved many of the above described problems associated with wooden pallets.
Cardboard pallets are typically very cost efficient. The wood pulp that is the basic component of the cardboard material is less expensive than the structural wood components of a typical wooden pallet. Most all cardboard products are recyclable so the raw material for a cardboard pallet could come from recycled sources and the cardboard pallet itself could be recycled.
Cardboard pallets may be used on surfaces that would otherwise be subjected to damage by wooden pallets. Cardboard pallets have a softer impact on both the surfaces they are placed upon and the cargo that is placed upon them.
Cardboard pallets are significantly lighter in weight than wooden pallets of similar size and design. A number of empty cardboard pallets could be easily handled by a single individual and the weight that a cardboard pallet adds to the overall weight of a cargo load is almost insignificant.
Some cardboard pallet designs have the additional capacity to be reused. In the past, the number of use cycles for a cardboard pallet was limited, but optimizing a cardboard pallet's structural integrity can extend the number of use cycles in certain environments.
Also significant, is the fact that once a cardboard pallet is damaged beyond the point that it can be safely used, the pallet is not a disposal problem and can be recycled to create the raw material for additional cardboard pallets. Because of its recyclability and low cost, a cardboard pallet would more likely be turned in for recycling at an appropriate time. Because of their non-recyclability and high cost, wooden pallets are frequently used beyond the point that they can safely or sufficiently handle cargo.
The problems associated with previous cardboard pallet designs have related primarily to their inability to hold up structurally as well as their wooden counterparts. There have likewise been problems associated with imitating the accessibility of the wooden pallet designs described above. It is, however, the lack of structural integrity that has to this point been the major barrier to a more widespread acceptance of the cardboard pallet.
Existing cardboard pallet designs are often limited to a very light load capacity. Their structural integrity generally deteriorates rapidly with use and usually restricts the pallet to a one time loading and unloading. For the most part, the structural soundness of a cardboard pallet has been directly related to its cost. Cardboard pallets that are capable of handling greater loads not only require a more complex construction and higher material costs, but also require significantly higher manufacturing costs. Cardboard pallets that approach a wooden pallet's structural integrity frequently have not only this disadvantage of additional cost, but have significant additional weight as well. Certainly, a solid slab of corrugated cardboard, the size and shape of a typical wooden pallet, could handle any load that a wooden pallet could handle. Unfortunately, such solid slabs of corrugated cardboard are impractical both from a cost perspective and from a handling and weight perspective. The required balance to be struck between structural integrity and cost and weight has heretofore not been met. No corrugated cardboard pallets have been able to optimize all of these factors.